Air conditioning



March 27, 1951 N. E. BERRY 2,546,382

AIR CONDITIONING Filed Feb. 2, 1946 v 3 Sheets-Sheet 1 IN VEN TOR.

March 27, 1951 BERRY AIR CONDITIONING 3 Sheets-Sheet 2- Filed Feb. 2, 1946 INVENTOR.

BY 20% a W March 27, 1951 N. E. BERRY 2,545,382

AIR CONDITIONING Filed Feb. 2, 1946 3 Sheets-Sheet s' INVENTOR.

f.) I I Patented Mar. 27, 1951 AIR CONDITIONING Norton E. Berry, Newburgh, Ind., assignor to Serve], Inc., New York, N. Y., a corporation of Delaware Application February 2, 1946, Serial No. 645,088

19 Claims. 1

The present invention relates to air condition ing and more particularly to the distribution of refrigerant in the evaporator of a refrigeration system arranged to condition a stream of circulating air.

While the present invention may be applied to other systems it is particularly adapted for use in a refrigeration system of the type illustrated and described in the U. S. Letters Patent to Albert R. Thomas et al. No. 2,282,504, issued May 12, 1942, entitled Refrigeration. In such a system refrigerant flows by gravity from the top to the bottom of an evaporator arranged in a circulating air duct. The evaporator comprises a plurality of substantially horizontal tubes connected in series so that refrigerant flows through each of the tubes in a tortuous path from the top to the bottom of the evaporator. As the air to be conditioned contacts the outside of the evaporator tubes its temperature will be lowered by the transfer of sensible heat to the relatively cold tubes and the air will be dehumidified to a degree dependent upon its wet bulb temperature by cooling a portion of the air below its dew point to condense the water vapor therefrom.

In such an air conditioner it is many times desirable to operate the refrigeration system at less than full capacity to dehumidify the air with minimum cooling. Under such conditions of operation the heat transfer surface of the evaporator remains constant so that all of the refrigerant supplied to the evaporator will be evaporated in the upper half thereof. The moisture removed from the air by contact with the outside of the refrigerated tubes at the upper half of the evaporator then drips onto the unrefrigerated tubes of the lower half and is re-evaporated into the air stream without practicall any removal of moisture from the air. As a result the air conditioning system operates to cool the air by evaporative cooling without removing moisture.

One of the objects of the present invention is to distribute refrigerant in the evaporator so that the moisture removed from the air by contact with the outside surfaces thereof will not be reevaporated into the air stream.

Another object of the present invention is to provide a refrigerant divider for delivering refrigerant to only a part of the evaporator when operating at less than full capacity and delivering refrigerant to the whole of the evaporator when operating at full capacity.

Another object is to provide a refrigerant divider of the type indicated adapted to deliver refrigerant at a predetermined rate to one section of the evaporator and deliver refrigerant supplied in excess of the predetermined rat to another section of the evaporator.

Another object is to provide an evaporator having a plurality of vertical sections with a refrigerant divider for delivering all of the refrigerant to one section at partial load and delivering refrigerant to the other sections successively as the load increases.

Another object is to provide an evaporator having a plurality of sections arranged one above the other and an arrangement for delivering all of the refrigerant to the lower half of the evaporator at partial load and to the upper and lower halves of the evaporator simultaneously at full load to prevent re-evaporation of moisture removed from the air.

Another object is to provide an evaporator through which refrigerant flows by gravity from the top to the bottom thereof and a refrigerant divider or regulator permitting a restricted flow of refrigerant to the middle of the evaporator and an unrestricted flow of any accumulated refrigerant to the top of the evaporator so that all of the refrigerant supplied will be delivered to either the middle or to the top of the evaporator.

Still another object is to provide an evaporator of the type indicated which is of simple and compact construction, adapted for economical manufacture, and operable over long periods of time without requiring repair or replacement of parts.

These and other objects will become more apparent from the following description and drawings in which like reference characters denote like parts throughout the several views. It is to be expressly understood, however, that the .drawings are for the purpose of illustration only and not a definition of the limits of the invention, reference being made for this purpose to the appended claims. In the drawings:

Fig. 1 is a diagrammatic view of an absorption refrigeration system incorporating the sectional evaporator and refrigerant divider of the pres ent invention;

Fig. 2 is an enlarged sectional view of the refrigerant divider illustrated in Fig. 1;

Fig. 3 is an enlarged transverse sectional view of a portion of the evaporator showing the tubes arranged in separate vertical rows or sections;

Fig. 4 is a transverse sectional View of an evaporator of modified construction showing the evaporator tubes arranged in upper and lower sections and the connections between adjacent tubes;

Fig, 5 is a sectional view similar to Fig. 4 showing the connections between adjacent tubes at the opposite end of the evaporator;

Fig. 6 is an enlarged View similar to Fig. 4 showing a refrigerant divider of modified construction;

Fig. 7 is a sectional view taken on line 'l| of Fig. 6 showing the metering device for delivering refrigerant at a predetermined rate from the bottom of the refrigerant divider trough, and

Fig. 8 is a longitudinal sectional view of the metering device taken on line 88 of Fig. 7.

Referring to the drawings, the present invention is shown applied to an absorption refrigeration system for conditioning air of the type illustrated and described in the Thomas patent, referred to above. Such a system operates in a partial vacuum and utilizes water as a refrigerant and a salt solution as an absorbent. Suffice it to state herein that the refrigeration system comprises a generator [0, condenser iI, evaporator I2, absorber I3 and heat exchanger Ill interconnected to provide a closed circuit for the circulation of refrigerant and absorbent. The generator III has a series of upright tubes [5 connected at their lower end to an inlet chamber I6 for absorption solution and connected at their upper ends to a separating chamber Il. Surrounding tubes I5 is a shell I8 providing a heating chamber I9 therebetween. Separating chamber I1 is connected to the condenser II by a conduit 29 and the condenser, in turn, is connected by a U- shaped conduit 2I to the evaporator I2 through a refrigerant divider H, later to be described in detail. The evaporator I2 communicates with the absorber I3 through passages or headers 22 and the space between the headers constitutes a part of an air duct through which the air to be conditioned is circulated.

Absorption solution weak in refrigerant or, in other words, a concentrated salt solution flows from the separating chamber IT to the top of the absorber I3 in a path of flow including the conduit 23, heat exchanger I4, and conduit 24. Ah.- sorption solution strong in refrigerant or, in other words, dilute solution flows from the bottom of the absorber I3 to the inlet chamber 16 of the generator I 9 in a path of flow including the conduit 25, heat exchanger l4, conduit 26, preheating vessel 2'! and conduit 28. The generator ID and condenser I I are maintained at a higher pressure than the evaporator I2 and absorber I3 by liquid columns in the conduits 2!, 24 and 25. In Fig. 1 the liquid level in the conduit 2i is indicated by the reference character X, the liquid level in conduit 23 connected to the conduit 24 through the heat exchanger [4 is indicated b the reference character Y and the liquid level in the conduit 25 is indicated by the reference character Z.

The absorber I3 and condenser II are cooled by cooling water from any suitable source such as a city main, cooling tower, or the like. The cooling water is supplied through a conduit 39 to a header 3| which supplies the cooling water to a bank of pipe coils 32 in the absorber I3. The cooling water from the coils 32 is delivered to a header, 33 and from the header it flows through a conduit 34 to the inlet chamber 35 of the condenser II. Cooling water from the condenser I I is discharged through the conduit 36.

The generator I0 is heated by steam supplied from a boiler 38 through a conduit 39 to the heating chamber I9. The upper end of the heating chamber I9 of the generator I0 is vented to the atmosphere by a vent pipe 40, and condensate drains from the lower end of the heating chamber through a drain pipe GI. Thus, steam is supplied to the heating chamber I9 of the generator ID at a predetermined constant pressure and temperature and its heat is transferred through the tubes IE to heat the absorption solution therein and expel refrigerant therefrom. The rate at which refrigerant is expelled from the absorption solution in the generator I9 is dependent upon the amount of steam supplied to the heating chamber I9 which, in turn, is dependent upon the amount of heat supplied to the boiler 38.

To adapt the refrigeration system to operate at varying capacities a plurality of burners are provided for heating the boiler which are operable singly or jointly. As illustrated, two burners A2, 43 are provided to adapt the system to operate at part capacity when the burner 92 alone is in operation and at full capacity when both burners are in operation. The burners may be controlled in any suitable manner and as herein illustrated they are controlled by fuel valves 44, 45 actuated by electrical means energized in response to the temperature of the ambient to be controlled. Each of the valves 44 and 45 has a magnetic plunger 46 on its valve stem which is actuated by a solenoid 41 to open the valve and by a spring 48 to close the valve. The solenoids ll for the valves 44, 55 are connected in parallel branch circuits to supply mains S, S1. The branch circuit for the valve 54 includes a conductor 49 connectin the supply main S to one side of the solenoid 41, a conductor 50 connecting the other side of the solenoid to a switch 5i and a conductor 52 conr meeting the switch to the other supply main S1.

The branch circuit for the valve 45 comprises a conductor 53, solenoid d1, conductor 54, switch 55 and conductor 56.

The switches 5| and 55 may be of any suitable Construction and for purposes of illustration they are shown as toggles with one arm of the toggle extending into slots-5i and 58 in an operating bar 59 and the arrangement is such that movement of the bar to the right as viewed in Fig. 1 will cause switch 5| to close and energize the solenoid 41 to open the valve 44 and thereafter close the switch 55 to open the valve 45. The bar 59 is actuated by a thermostat comprising a bulb 69 subjected to the temperature of the ambient and an expansible bellows BI connected by a capillary tube 62. The expansible bellows BI is connected through a rod 63 to one end of a pivoted lever 66 and the opposite end of the lever extends into a slot 65 in the bar 59. The bulb 69 contains a volatile liquid which increases the pressure therein directly in proportion to increases in temperature to expand the bellows 9! and thereby rock the lever 64 to slide the bar 59 and close the switches 5i and 55 successively. A spring 56 operates the bellows 6! upon a decrease in pressure to rock the lever 54 and slide the bar 59 to open the switches 55 and 5! successively.

In accordance with the present invention the evaporator I2 is divided into separate sections A and B through which refrigerant flows by gravity. The evaporator I2 is located in an air duct through which air is caused to circulate and comprises a series of substantially horizontal tubes 68 extending between the spaced headers 22 with vertical fins B9 connecting the tubes, see Fig. 1. For the purpose of illustration the tubes 38 of the evaporator I2 are shown in the embodiment of theinvention illustrated in Fig. 3 as arranged in two vertical rows in parallel side by side relationship to provide the separate sections A and B, but it is to be understood that each section may include more than a single row of tubes. The ends of the tubes 68 project through the walls of the headers 22 to which they are sealed and refrigerant flowing from the end of each tube of a row or section is directed into the end of the next lowermost tube of the section by a series of cups in the headers. The cups 10 are arranged to receive refrigerant from the ends of alternate tubes in the opposite headers so that they connect the tubes in series for gravity flow of refrigerant through each tube from the top to the bottom of the section.

Between the end of the U-shaped supply pipe 2| and the top of the evaporator i2 is a refrigerant divider or regulator 1| comprising a rectangular box or vessel 12 supported on a vent pipe 13 extending upwardly from one of the headers 22, see Figs. 1 and 2. A septum plate or dam I4 is provided in the vessel 12 to form separate chambers 15 and 16. The end of the U-shaped conduit 2| opens into the vessel 12 above the chamber 15 and a baffle 71 adjacent the end of the conduit 2| directs all of the liquid refrigerant supplied from the condenser into this chamber. Preferably a screen 18 covers the top of chamber 15 to filter out any scale or foreign matter which may be introduced with the refrigerant. A conduit 19 connects the bottom of the chamber 15 to a cup 10 for introducing refrigerant into the uppermost tube 68 of the row of tubes constituting section A of the evaporator, see Figs. 2 and 3. The conduit 19 is provided with a U-shaped bend 80 to provide a liquid trap and a measuring orifice 8| in the trap limits the rate at which refrigerant is delivered from the chamber 15 to section A of the evaporator I2. The measuring orifice 8| is so dimensioned that with a liquid level in the chamber 15 adjacent the top of the dam 14 it will deliver refrigerant continuously at a predetermined constant rate corresponding to operation with one burner to supply refrigerant to substantially all of the tubes 68 of the row or section A. In other words, the coil sections A and B are designed to utilize all of their heat transfer surface to evaporate the refrigerant delivered thereto at full input by both burners 42 and 43 so that all of the surface area of section A will be required toevaporate the refrigerant delivered at half input by one burner. A similar conduit 82 having a trap 83 connects the bottom of the chamber 16 of the refrigerant divider II to the other row or section B of tubes 68 of the evaporator. One embodiment of the invention having now been described in detail the mode of operation is explained as follows.

When the control switches 5| and 55 are in theposition illustrated in Fig. 1, the refrigeration system is inoperative. As the temperature of the air to be conditioned increases the volatile fluid increases the pressure in the thermostat to expand the bellows 6|. As the bellows 6| expands it operates through the rod 63 and lever 64 to slide the bar 59 toward the right as viewed in Fig. 1. Sliding movement of the bar 59 will actuate the toggle switch 5| to closed position and thereby energize the solenoid 41 to open the fuel valve 44 and heat the boiler 38 to generate steam.

Steam generated in the boiler 38 will be su-pplied through the conduit 39 to the heating chamber [9 of the generator II] and transmit its heat through the tubes |5 to expel refrigerant vapor from the absorption solution therein. 'As

the refrigerant vapor is formed it rises in thecenter of the tubes 9 at considerable velocity and lifts absorption solution at the sides of the tubes by a climbing film action. The refrigerant vapor is separated from the absorption solution in the separating chamber I1 and flows through the conduit 20 to the condenser II where it is condensed to a liquid. The liquefied refrigerant fiows from the condenser through the U- shaped tube 2| to the refrigerant divider Due to the arrangement of the chamber I5 and the bafile 11 all of the refrigerant supplied from the condenser enters the chamber 15 of the refrigerant divider. The refrigerant entering the receiving chamber 15 is delivered through the conduit 19 to the uppermost tube of the row orsection A of tubes 68 in the evaporator l2. the measuring orifice 8| is of such size as to permit a rate of flow of refrigerant when theliquid level is adjacent the top of the dam 14 corresponding to the amount supplied at part capacity with one burner 42 in operation, all of the refrigerant is supplied to the section A of the evaporator 2.

The refrigerant enters one end of the uppermost tube 68 of the evaporator l2 and flows by gravity through each tube in series from the top to the bottom thereof. At the time refrigerant is supplied to the interior of the tubes 68 of the evaporator l2, air is caused to circulate over the exterior of the tubes and fins 69. The heat transfer surface of the tubes 68 of section A is designed to'evaporate the amount of refrigerant supplied when the boiler 38 is heated by the single burner 42 so that refrigerant will be supplied to substantially all of the tubes from the top to the bottom of the evaporator section- Furthermore, the interior of the tubes 68 in the evaporator section A are in open communication with the absorber l3 so that the refrigerant in the tubes will evaporate at and have a low temperature corresponding to the pressure in the absorber. Thus, relatively cold tubes 68 of section A of the evaporator |2 extend over the entire cross-sectional area of the air stream, see Fig. 1. The portion of the air directly contacting the outside of the relatively cold evaporator tubes will be cooled below its dew point so that moisture will be condensed thereon to dehumidify the air. The moisture removed from the air will drip from tube to tube from the top to the bottom of section A of the evaporator I2 where it will be drained to a waste pipe, not shown. Due to the fact that substantially all of the tubes 68 of the section A are supplied with refrigerant and relatively cold, the moisture removed from the air will not be re-evaporated into the air stream as it drips from tube to tube to the bottom of the evaporator.

As the heat is transferred from the stream of air to the refrigerant in the evaporator tubes 68, the refrigerant evaporates therein and the refrigerant vapor is absorbed in the absorber i3. Absorption solution is continuously supplied to the absorber l3 from the generator ID in a path of flow from the separating chamber ll through the conduit 23, heat exchanger I4, and conduit 24 to the top of the absorber where it is distrib uted and flows downwardly over the bank of coils 32 therein.'- The spreading of the absorption solution over a relatively large surface area on the banks'of coils 32 promotes the absorption of refrigerant vapor as it flows from the ends of the tubes 68 and through the headers 22 to the absorber.

The absorption solution enriched with r assess:

i absorbed refrigerant then flows from the bottom of the: absorber through: the conduit. 25, heatexe changer l4; conduit. 26, preheating leveling pot- Zt'l? andnconduitlzsto the inlet chamber l6' atlthe baseof the generator H).

The refrigeration system continues to' cooliand dehumid-ify: the airas itv flows over the evaporator #21 If 'the'temperature. of" the: air continues; to riseithebellows 6| of the thermostat continues to expand. and. slide the bar 59 further to the. right as'viewed' in Fig. I to close the switch: 55. When the switch tdis closed the secondele'ctric' branch circuit including the-solenoid; M. is energized' to: open. thev valve 45- and. initiate operation of: the. burner 43. The refrigeration systemith'en. operates. atv full capacity and the increased amount of. steam generated in the boiler tsan'd: delivered: to" the generator Hi: increases the amount: of refrigerant expelled in the generator tubes It, condensed in the condenser Ll: and:sup plied to the chamber in the refrigerant divider. Hi: As the. refrigerant is supplied to the chamber 15 atv a. faster rate than it is delivered. through measuring orifice 8| in the conduit lg; there-- frigerant will flow over the dam I iinto the chamber 76. Refrigerant thenwill flow from the chamber-16 through the conduit 82' to the top 'of the other sectionBof the evaporator [2. The re-' frigerant flows by gravitythrough each of the tubes B8'of section Bof theevaporator I2 in suc cessi'oninthe same manner as explained with respect to the section A to further cool and dehumidify the air passing over the evaporator tubes;

The 'refrigeration system will continue to operate at full capacity until the air' is cooled suffici'ently to: decrease its temperature. Upon decrease in the air temperaturethe spring 6'6"com-- pressesthe bellows 6! of the thermostat and operating through the rod 63 rocks the lever 64' to-slide the control bar 59 toward the left as viewed in Fig. I to firstopen' the switch 55 to out out the burner 43 and thereafter open the switch 5! to out out'theburner 42.

Thus, the refrigerant divider H receives all'of the-refrigerant supplied from the" condenser H and'd'elivers refrigerant to section A of the evapo-- rator [2 at predetermined rate corresponding to theheat'transfer surface of the section and delivers all refrigerant supplied in excess of the predetermined'rate to section B of the evaporator whereby to insure refrigeration in each tubeof section A.

In accordance with the present invention the evaporator may be divided into vertical sections as illustrated and described in connection with Figs. 1 and 3 or'the' evaporator may be divided into the upper and lower sections as illustrated in Figs. 4 and 5. In the embodiment of the invention illustrated in Figs. 4 and 5, the evaporator tubes 58 are all connected in seriesb'oth laterally and vertically so thatrefrigerant supplied to the uppermost tube will flow by gravity through each tube successivelyto. the lowermost" tube. The uppermost tube-BB, see Fig. 4,- is sup plied with refrigerant fromta' cup 10.. The refrigerant flows lengthwise. through thetube 58" into a cup 16a at theopposite end ofi'theevaporater, see Fig. 5; which. directs it? into the next laterally adjacent tube fita'arran'ged at a. slightly lower level than the". first.v tube. The; refrigerant flowing from the end of the second tube 68a is delivered into a cup -lfi'bwhic'h, inturn, directs it. into: the next adjacent. or; third lateral tube 681), see Fig; .4. From theoppositecend.oftheithirdstube.

EBbithemefri'gerant enters a: cup roewmcn. directs the refrigerant into the". next: or fourth laterally adjacent tube-68c. From the end of the last tube the refrigerant enters: a cup- 10d. which is con nected'itoia' cup we directly bel'owthe first men-- tioned cup it by aapipe 8'4; seeFig.- 4.. The re-x frigerant then. flows through the next" lateraLrovv' ofl'tubes in the manner previously described and from that to :the: next lowermost row throughout thexl'engthor the evaporator.

In: this. embodiment of the inventionthecon duiti'la delivers refrigerant from the cnamberfle to an end cup Hi-f par-t way'betweenthe top' and the: bottom .of the evaporator I 2; Similarly'the conduit? 82': delivers refrigerant from the chemberi T6 of. the: refrigerant divider 12-to the-up er: most cup 10 of the evaporator-12; Thus, ati-part load all ofthe refrigeranti delivered for flow throughthelower section of the evapo'ratoronly and: at full load the refrigerant is delivered for flow through the upper andlower sections of the evaporator simultaneously. Therefore, at part' load any moisture condensed fromthe air stream will drip'over the relatively coldtubes- 68 at the lower section of'the evaporator 12 and be drained therefrom withoutre-evaporation into the air stream'. However, at full load both the upper and lower sections of the evaporator l2- will be efiiective to cool and dehumidify the air.

In Figs. 6 to 8 a modified constructionof re iri'gerant? divider or flow regulator is shown applied to an evaporator l2- similar toth'at"il1us' trated': in Fig.4.. However, the two u-ppermo's't tubes 63 and" Gta of the evaporator illustrated in Fig; 6: constitute flash chambers into which re fri'gerant'iis delivered from branches 21a,- and 21b" of the U.-shaped conduit 2!. The refrigerant flows through theflash tubes into a trough or vessel. 85- in the rearward header 22. As illustrated .in Fig 6, the bottom 86 of the trough 85 is: inclined downwardly andthetrough encloses the first three laterally adjacent tubes 68, 6821 and 68b. The. third and fourth tubes 68b and 680 of .Tthe: firstlateral row of tubes are connected by. a cup 18a in thema'nner: described with re-" pect-itozthe' evaporator illustrated in Figs; land 5' an'di'the'remainingltubes' are also connected in a. like manner. A delivery conduit 81 connects the' lowest point of thebo'ttom wall 86- of the trough: 85fto a metering device 88. The meter ing device 88'comprises an inlet chamber 89' to whichithedelivery' pipe Bl'i'sattached', see Fig. 8', a septum sflihavinga measuring orifice 9 therein and an outlet chamber 92 above the septum. Preferablma cylindrical screen 93 is providedin the inlet chamber 89 through which the refriger ant passes before entering the measuring orifice 91-. Azco'nduit 95, see-Fig; 7, connects theoutlet chamber 9:2"toa cup 7E3) midway betweenthe'top' and thebottom of the evaporator as in'the formof evaporator illustratedin Figs; 4 and 5';

The form of' refrigerant divider or regulator I l illustrated'in'Figs. .6 130.8 operates 'in' azmanner similarto" the form illustrated in" Figs.- 4 and 5 in-.that refrigerant is, supplied to the trough 85: and is deliveredatia predetermined rate for flow to-th'elower. partof the evaporator l2; When": refrigerant is supplied ata faster ratethan it is" delivered through the? measuring orifice 9| it-- backs up in the trough 85 and overflows into= the'endioffthe thirditube 68b. Refrigerantentering the third tube 68b. then flows through the upper part ofithe evaporator I21. Thus, at part loads: refrigerant is'supplie'dito the lowerisectio'nl 15 of. the: evaporator only and: at-fu11load1refriger ant is supplied simultaneously to the upper and lower sections. With such an arrangement, moisture removed from the air at partial operating capacity will not be reevaporated into the air stream. The orifice 9| provides a restricted path of flow for refrigerant to the lower half of the evaporator while the tube 68b provides an unrestricted path of flow to the top of the evaporator for any accumulated refrigerant rising in the vessel 85 to the level of the tube. Thus, if

the orifice 9| should become plugged or if for any other reason the refrigerant does not flow properly to the lower half of the evaporator, the refrigerant will then flow through the unrestricted tube 6% to the top of the evaporator so that all of the refrigerant supplied from the condenser will be delivered to the evaporator through one or the other of the two paths of flow.

It will now be observed that the present invention provides a novel construction and arrangement of elements to adapt refrigerant to be supplied to one section of an evaporator only at partial load and to a plurality of sections at full load whereby to prevent moisture removed from the air stream from being re-evaporated therein. It will further be observed that the present invention provides a refrigerant divider for supplying refrigerant at a predetermined rate to one of the sections and delivering all refrigerant supplied in excess of the predetermined rate to another section of the evaporator. It will still further be observed that the present invention contemplates the division of the evaporator into a plurality of vertical sections or a plurality of horizontal sections arranged one above the other.

While several embodiments of the invention are herein described, it is to be understood that further modifications may be made in the construction and arrangement of the elements without departing from the spirit and scope of the invention. For example, instead of dividing the evaporator and refrigerant divider into two sections it may be divided into a greater number of sections so as to successively bring in additional sections as the load increases. Therefore, without limiting myself to this respect, I claim:

1. In an absorption refrigeration system of the type which operates in a partial vacuum and utilizes water as a refrigerant and a salt solution as an absorbent, an evaporator having a plurality of sections through which refrigerant flows by gravity, means for supplying refrigerant, a refrigerant divider above the evaporator and adapted to receive refrigerant from the supplying means, a connection between the refrigerant divider and one section of the evaporator for delivering refrigerant thereto at a predetermined rate, and another connection between the divider and another section of the evaporator for delivering refrigerant thereto when the liquid in the divider rises above a predetermined level.

2. In an air conditioner, a refrigerant evaporator having a series of vertical sections arranged in side by side relationship in an air duct, means for supplying liquid refrigerant at varying rates for partial and full load conditions corresponding to the cooling capacity of the sepa-.

rate sections, and a refrigerant divider for receiving all of the liquid refrigerant from the supplying means and having a conduit with a restriction therein to deliver all of the refrigerant to one of the evaporator sections at partial load to dehumidify the air by cooling at least a portion of the air below its dew point, and said refrigerant divider having an unrestricted conduit operable to deliver accumulated refrigerant to another section of the evaporator at full load whereby substantially the entire surface of said one section is supplied with refrigerant at partial load to prevent re-evaporation of moisture removed from the air.

3. In an air conditioner, a refrigerant evaporator for dehumidifying the air to be conditioned by cooling at least a portion of the air below its dew point, said evaporator having a plurality of vertical rows of substantially horizontal tubes, the tubes of each row being connected to permit refrigerant to flow therethrough by gravity, means for supplying liquid refrigerant, and a refrigerant divider comprising a vessel for receiving the refrigerant from the supplying means, a restricted connection between the vessel and the uppermost tube of one of the rows of evaporator tubes for delivering liquid refrigerant thereto at a predetermined rate sufficient to insure a supply of refrigerant to substantially all of the tubes of the row, and an unrestricted connection between the vessel and the uppermost tube of another row of tubes for delivering liquid refrigerant thereto when the liquid in the vessel rises to a predetermined level whereby to prevent reevaporation of moisture removed from the air when the conditioner operates at less than full capacity.

4. In an air conditioner, a refrigerant evaporator for dehumidifying air to be conditioned by cooling at least a portion of the airbelow its dew point, said evaporator having a plurality of vertical rows of substantially horizontal tubes, said tubes of each row being connected to permit refrigerant to fiow therethrough by gravity, a refrigerant divider having a vessel with a partition wall therein to divide it into separate. chambers, means for supplying liquid refrigerant at different rates for operation at part and full capacity to one of the chambers, a connection between said one chamber and the uppermost tube of one of the rows of evaporator tubes for delivering liquid refrigerant by gravity flow at a predetermined rate sufficient to insure a supply of refrigerant to substantially all of the tubes of the row, and an unrestricted connection between the other chamber of the vessel and the uppermost tube of another row of tubes for delivering refrigerant overflowing the partition wall into the second chamber by gravity flow whereby to prevent re-evaporation of moisture removed from the air by the saidone row of tubes when refrigerant is supplied at part capacity.

5. In an air conditioner, a refrigerant evaporator for dehumidifying air by cooling at least a portion of the air below its dew point, said evaporator having a plurality of sections arranged one above the other and connected in series so that refrigerant may flow continuously through successive sections, means for supplying liquid refrigerant at varying rates, and a refrigerant divider for receiving the refrigerant from the supplying means and having a conduit for delivering refrigerant at a predetermined rate corresponding to the cooling capacity of the lower section to the top thereof for flowv therethrough by gravity, and said refrigerant divider-having a second conduit for delivering all refrigerant sup' plied over the predetermined rate to the top of the upper section for fiow'through successive sections by gravity, whereby to prevent re-evaporation of moisture removed from the air during operation of the unit at partial capacity.

:6. In an air conditioner, a refrigerant evaporator for-dehumidifying air by cooling at leasta .portion of the air below its dew point, said evaporator having a pluralityof substantially horizontal tubes connected to each other to permit refrigerant to flow through each of the tubes in series from the top to the bottom of the evaporator, means for supplying liquid refrigerant at varying rates, and a refrigerant divider having a determined rate corresponding to the cooling .ca-

pacity of said portion, and an unrestricted connection between the refrigerant divider vessel and the top of the evaporator for delivering refrigerant thereto when the refrigerant rises to a predetermined level in the vessel whereby only the lower portion of the evaporator is cooled at partial capacity to prevent re-evaporation of moisture removed from the air and all refrigerant not delivered to the lower section is delivered automatically to the upper section.

7. In an air conditioner, a refrigerant evaporator for dehumidifying air by cooling at least atportion of the air below its dew point, said evaporator having a plurality of substantially horizontal tubes connected to each other to permit refrigerant to flow througheach of the tubes in series from the top to the bottom of the evaporator, a refrigerant divider having .a vessel with a partition wall-therein todivideit into separate chambers, means for supplying liquid refrigerant at diiferentrates to one of the chambers for operation at part and full capacity, a restricted connection between said one chamber and the evaporator for delivering refrigerant to anintermediate point of the evaporator for gravity flow through the lower part thereof at a predetermined rate corresponding tothe cooling capacity of said part, and an ,unrestricted connection between the other chamber and the top of the evaporator for delivering refrigerant overflowing the partition wall for gravity flow through the upper parttof the evaporatorrwhereby to prevent re-evaporation of moisture removed from-the air at partial capacity.

8. In an air conditioner, a refrigerant evaporator for dehumidifying .air by cooling at least a portion of the air below its. dew point, said evaporator having ,a plurality of substantially horizontal tubes, means for connecting groups of the tubes to provide separate sections, ,a conduit for supplying liquid refrigerant at varying rates to one end of at least one of the tubes for gravity flow therethrough, a vessel at the opposite end of thetube forvreceiving refrigerant flowingthrough said tube, a connectionfrom the bottom of said vessel to onesection of the evaporator for delivering refrigerant at a predetermined rate corresponding to itscooling capacity for ,gravity flow therethrough, and a tube connectedto said-vessel at a level above thefi-rst mentionedconnection for delivering refrigerant for gravity flow through another section of the evaporator when the liquid rises to a predetermined level 'in the vessel whereby to prevent reevaporation of .moisture removed from the air when the conditioner operates at .less than full capac ty.

9. In an air conditioner, a refrigerant evaporator for dehumidifying .air by cooling at least a portion of the air below. its dew point, saidevap- --or at or having .a plurality of substantially horizontal tubes, means for supplying refrigerant at different rates to operate the air conditioner at part or full capacity, a conduit connected to one endof at least one of the tubes for delivering the refrigerant for gravity flow therethrough, the remainder of the tubes being connected to permit refrigerant to flow through each tube by gravity from the-top to the bottom of the evaporator, a vessel 'connectedto the opposite end of the first mentioned tube for receiving refrigerant flowing therefrom, a connection from the bottom of said vessel to anintermediate point of the evaporator ,for delivering refrigerant for gravity flow through the lower portion thereof at a predeterminedtrate corresponding-to the cooling capacity ,of said portion, and a-tube connected to said vessel above the bottom thereof for delivering refrige erant to the upper portionof-the evaporator when the liquid rises ,to .a predetermined level in the vessel for operation at full capacity wherebyto prevent reevaporation of moisture removed from the air during operation at'partial capacity.

1.0. In an air conditioner, .a refrigerant evaporator for dehumidifying air by coolingat least a portion of theair-below its ;;dew point, said evaporator having a plurality of substantially horizontal tubes, means for supplying refrigerant at different rates for operation at part full capacity, a conduit connected to one end of at l a n f t bes for d ivering the refri erant for gravity flow ,thereth-rough, the remainderof the tubes being connected to adapt refrigerant to flow through each of the tubes :in series from the top to th bottom of the evaporator, a vessel connected to the opposite .end of the first mentioned tube for receiving refrigerant flowing thereth-rough, a connection between :the bottom of the yessel and an intermediate :point of the evaporator, a metering orifice in said connection for permitting the flow of refrigerant to said intermediate point of the evaporator for g v yw through the flower section of tubes at a predetermined rate =.eor.ersponding :to thecooling capacity of said section, and said vessel 10011- necting said first tube to an adjacent tube Tata point above the bottom for delivering refrigerant for gravity flow through the upper section of tubes when the liquid rises to a predetermined level in the vessel whereby to prevent ireevaporation of moisture removedfrom t'he :ai-rduringlom eration at part capacity.

1-1. In a refrigeration system, an evaporator comprising a plurality of substantially horizontal tubes through which refrigerant flows by gravity, means for supplying-liquidrefrigerant to one end of at least oneyof the uppermost tubes, theends of the'remainderof the tubes being connected'in series -to adaptrefrigerant to flow from the top to the bottom of the evaporatona :vessel at the opposite end .of the first mentioned tube for receiving refrigerant flowing therefrom, a connection from the bottom of said vessel to a tube intermediate the top and bottom thereof, said connection restricting flow to deliver refrigerant at a predetermined rate for gravity flow through the lower part of the evaporator, and one endof the tube adjacent the uppermost tube being corinectedto the vessel abovethe bottorn thereof for deliveringrefrigerant-tattle upper portion of the evaporator when the liquid rises to a predetermined level therein whereby to cool only the lower portionof the evaporator atpartial load and both the upper andlower portions at full load and insure delivery of all of the re- 13 frigerant to either the upper or lower sections of the evaporator.

12. In an air conditioner, a cooling element for cooling and dehumidifying the air by cooling at least a portion of it below its dew point, said cooling element having a plurality of separate sections contacted by the air, means for supplying cooling medium at varying rates, and a liquid divider for receiving all of the cooling medium supplied and continuously delivering the cooling medium to one of the sections at a predetermined rate corresponding to the cooling capacity of said section and thereafter delivering all excess cooling medium to another section so that the entire surface of said one evaporator section will be cooled to maintain all moisture condensed thereon at a temperature below the dew point of the air to prevent reevaporation.

13. In an air conditioner, a refrigerant evaporator for cooling and dehumidifying air by cooling at least a portion of it below its dew point, said evaporator having a pluralityof separate sections contacted by the air to be conditioned, each of said sections having overlying portions so that moisture condensed on one portion will drip onto the next lowermost portion from the top to the bottm of the section, means for supplying refrigerant at varying rates, and a refrigerant divider for receiving all of the refrigerant supplied and continuously delivering the refrigerant to one of the sections at a predetermined rate corresponding to the cooling capacity of said section and thereafter delivering all excess cooling medium to another section so that all portions of said one section will be cooled to maintain moisture condensed thereon at a temperature below the dew point of the air as it drips from successive portions to prevent reevaporation.

14. In an air conditioner, a refrigerant evaporator for cooling and 'dehumidifying air by cooling at least a portion of it below its dew point, said evaporator having a plurality of separate sections for cooling air directly contacting the same, means for supplying liquid refrigerant at varying rates, a refrigerant divider connected to receive all of the liquid refrigerant from the supplying means, a first conduit connecting the refrigerant divider to one of the evaporator sections to continuously deliver refrigerant to the latter, said conduit having an internal construction to limit the flow of refrigerant to a predetermined rate corresponding to the evaporative capacity of said section, a second unrestricted conduit connecting the refrigerant divider and another section of the evaporator, and means in the divider to limit flow to said first conduit until the refrigerant supplied exceeds the predetermined rate of flow therethrough.

15. In an air conditioner, a refrigerant evaporator for cooling and dehumidifying air by cooling at least a portion of it below its dew point, said evaporator having a series of substantially horizontal tubes arranged one over the other, the tubes being arranged in sections so that refrigerant may flow through the tubes of each section in series, means for supplying refrigerant at varying rates, and a liquid divider for receiving all of the refrigerant supplied and continuously delivering the refrigerant to one of the sections at a predetermined rate corresponding to the cooling capacity of said section and thereafter delivering all excess refrigerant to another section so that all of the tubes of said one section will be cooled to prevent reevaporation of con- 16. In an air conditioner, a refrigerant evaporator for cooling and dehumidifying air by cooling at least a portion of it below its dew point, said evaporator having a plurality of separate sections contacted by the air to be conditioned, means for supplying refrigerant at varying rates, a refrigerant divider comprising a vessel for receiving the refrigerant from the supplying means and having a conduit with a restriction therein to continuously deliver refrigerant to one of the evaporator sections at a predetermined rate corresponding to its evaporative capacity, and said refrigerant divider having a second unrestricted conduit connected to deliver refrigerant to another section when the refrigerant rises above a predetermined level in said vessel.

17. In an air conditioner, a refrigerant evaporator for cooling and dehumidifying air by cooling at least a portion of it below its dew point, said evaporator having a plurality of separate sections contacted by the air, means for supplying refrigerant at varying rates, a refrigerant divider for receiving the refrigerant from the supplying means, a conduit between the liquid divider and one of the sections of the evaporator and having a metering orifice therein for con tinuously delivering refrigerant from the divider to the evaporator section at a predetermined rate corresponding to the evaporative capacity of said section, and another conduit between the divider and another section of the evaporator for delivering to the latter all refrigerant supplied in excess of the predetermined amount delivered to the one section through the metering orifice.

18. In an air conditioner, an absorption refrigeration system having a generator, a condenser, an evaporator and an absorber interconnected for the circulation of refrigerant and absorbent therein, means for varying the rate at which heat is supplied to the generator to vary the rate at which liquid refrigerant is delivered from the condenser, said evaporator having a plurality of sections through which refrigerant flows by gravity for cooling and dehumidifying air by cooling at least a portion of it below its dew point, a refrigerant divider connected between the condenser and evaporator for receiving all of the refrigerant supplied from the condenser and having a connection for delivering refrigerant to one of the evaporator sections at a predetermined rate corresponding to the evaporative capacity of said section, and said refrigerant divider having a connection for delivering refrigerant to another section of the evaporator when the rate of supply thereto exceeds the predetermined rate at which refrigerant is delivered to said one section.

19. In an air conditioner, a vacuum type absorption refrigeration system utilizing water as a refrigerant and a salt solution as an absorbent and having an evaporator cooled by the evaporation of refrigerant therein to a temperature above freezing, said evaporator having a plurality of separate sections for cooling and dehumidifying air by cooling at least a portion of it below its dew point, means for supplying refrigerant at varying rates, and a liquid divider for receiving all of the refrigerant supplied and continuously delivering refrigerant to one of the sections at a predetermined fixed rate corresponding to the cooling capacity of said section and thereafter 1:5 1 6 delivering allgexoesos refrigerant-12o another sec UNITED SLATES PATENTS tion so that the entire surf,ace of said one evapo- Number Name Date rator section will be maintained at a, temperature 1176 Davenport July 1930 below theflew point of the air 'to prevent reevap- 5 3 m 9 oration of moisture'condensed:thereon. 6 McLehegan a 193.8

I w 1.4 2,133,964 Buchanan Oct. '25, '1938 NORTON IEEBRY ;2 1s6;s 13 Gibson July 18, 1939 337.9334 Ullstrand Nov. 14, 1939 REFERENCES CITED 2,345,505 Sied-le Mar. 28, 1944 The following references are of record In =the 10 2;3-5 1;700 Patterson June 0 1.944

file of this patent: 2301,300 Gross V V June 4 19:16 

